Known grinding rollers for roller or rolling mills generally have a radially inner body and a radially outer roller body. The concept of the radially inner body also covers in this connection a base jacket, which can be fixed to the said body.
On the radially outer roller body is formed a rolling surface, which forms a grinding surface cooperating with a rotary grinding disk or a further grinding roller.
The radially outer roller body must have an extremely high wear resistance. This is brought about by using extremely hard, but at the same time extremely brittle fracture-sensitive materials, which are cast. In many cases such materials additionally undergo a special heat treatment.
However, it has been found that roller bodies made from such materials are highly subject to breakage. The essential reasons for this are internal casting stresses as a result of nonuniform cooling from the outside to the inside, structural stresses due to uncontrolled heat treatments, keying or shrinkage stresses due to mechanical joining by means of conical force fits and the bending loads occurring during joining by means of cylindrical seats with the necessary assembly clearance. Other influencing factors are the rapidly fluctuating temperatures during the grinding process and working stresses, particularly in the case of grinding material requiring high, specific grinding pressures, such as e.g. cement, slag and cement precrushing. As a rule several of the aforementioned factors act in conjunction.
For avoiding breaks and the resulting secondary damage, such as e.g. damage caused by dropping fragments, it is known to use segmented, radially outer roller bodies. However, the disadvantage is then encountered of the high cost manufacture of such segmented roller bodies. As each individual segment has to be individually worked both with respect to its bearing surface and with respect to its two contact faces with the neighbouring segments in a highly precise manner, the necessary time expenditure has a disadvantageous effect on the manufacturing costs.